1. Field of the Invention
The present invention relates to a screen filter and, more particularly, to a filter for sifting or filtering powder or granular substances or the like.
2. Description of the Prior Art
Mechanical revolving screens and vibrating screens have been proposed in the prior art for industrial use as screen filters for filtering powders, granular substances and the like. While such screens satisfactorily achieve such basic functions as sorting out or filtering mixtures into groups according to the granular sizes thereof, they are defective in filtering adhesive substances, such as powdered detergent, since such materials tend to stick to the screen causing clogging of the mesh.
When the mesh becomes clogged, the substances to be filtered accumulate on the screen filter, thereby deteriorating the operational efficiency. Furthermore, the clogged mesh needs to be cleaned, requiring additional time and labor expense for the personnel in charge of such cleaning. Moreover, in performing the cleaning operation, workers are forced to work in a dust-hazardous environment as dust is expelled into the air when the dust cover over the filter is removed for cleaning.